Technical Abstract:
The model plant Arabidopsis thaliana has provided unique opportunities to explore and unravel many key biological features of plant biology including disease resistance. However, the inability of rust fungi of the genus Puccinia to infect Arabidopsis has prevented its use in exploring grass-rust interactions. The model plant Brachypodium distachyon is a member of the same grass subfamily as the principal cool-season grain crops, and has been reported to be infected by various Puccinia species. We have focused our efforts on establishing Brachypodium as a model for exploring grass-Puccinia graminis interactions. Brachypodium can be successfully infected by different formae specialis of stem rust including P. graminis f. sp. tritici. Natural variation for resistance and susceptibility to stem rust exists in Brachypodium and efforts are underway to decipher the genetic basis for this variation using recombinant inbred populations from parents with differing levels of resistance. Similarly, induced mutants with compromised stem rust resistance have been identified and are now being employed within a program to understand the molecular biology of stem rust resistance and susceptibility. Our results to date suggest that Brachypodium holds promise as a model for advancing our understanding of stem rust resistance.